1. Field of the Invention
The present invention relates to an Internet telephone system, a call connection controller, a terminal association method used therein, and its program. In particular, the present invention relates to a method of associating an existing extension telephone and a personal computer having an Internet telephone function.
2. Related Art
Conventionally, as a method of associating with this type of personal computer (hereinafter referred to as PC), there is one in which a voice input/output port and a MIDI (Musical Instrument Digital Interface) port, of a sound card installed in an extension slot of a PC, are connected with the main body of a handset (see, for example, the Japanese Patent Application Laid-open No. 2000-115354 (pp.4-5, FIG. 1), hereinafter referred to as Patent Document 1).
The main body of the handset is equipped with a speaker and a hook switch and is capable of being connected with a sound card. In a case of the sound card being connected with the main body of the handset, the voice input/output port and the MIDI are connected with the speaker and the handset, and a voice input/output mode, corresponding to on-hook information from the hook switch or signals indicating the on-hook information, is used.
In another association method with a PC, IP (Internet Protocol) telephones as communication terminals and PCs corresponding to the respective IP telephones are interconnected over a LAN (Local Area Network), and with a control by the PC, an IP telephone corresponding to the PC is associated (see, for example, the Japanese Patent Application Laid-open No. 2002-199026 (pp.9-10, FIG. 1), hereinafter referred to as Patent Document 2).
FIG. 1 shows a call operation between terminals through a PBX (Private Branch Exchange) which is a typical call connection controller. In FIG. 1, a call between a first terminal 91 and a second terminal 92, each of which is a radio mobile terminal, is made in such a manner that the terminals are connected with the PBX 6 via radio base stations 81, 82, and a voice path between the two terminals is defined by a connection switch (not shown) in the PBX 6. In a case that the first terminal 91 and the second terminal 92 are fixed-line terminals, the first terminal 91 and the second terminal 92 are interconnected over a line of the PBX 6.
FIG. 2 shows an exemplary structure of a typical Internet telephone system. In FIG. 2, a PC 7 includes, a voice input/output unit 71, a communication interface (I/F) 72 which transmits/receives Internet telephone information over an Internet line 200 such as a LAN, and a control software 73 for transmitting/receiving call control information between the PBX 6.
Conventionally, when making a call using an Internet telephone, dialing the receiver's number from a keyboard 74 connected with the PC 7, or activating an application such as a telephone book so as to perform an originating manipulation.
A call is realized by using a handset 75 connected with the voice input/output unit 71. Voice information is transmitted/received with a use of the Internet line 200 such as a LAN via the handset 75 and the PC 7. In a case that there are terminals accommodated in the PBX 6, for example, the first terminal 91 and the second terminal 92 which may be radio mobile terminals such as PHS (Personal Handy-phone System) or fixed-line terminals, a user holds two devices, that is, the handset 75 and the terminal 91. Further, extension numbers managed by the PBX 6 are assigned to the two devices, that is, the handset 75 and the terminal 91, respectively, so that it may be troublesome for the user to manage terminal devices and telephone numbers.
Further, in the aforementioned Internet telephone system, voice information is to be transmitted/received over the Internet line 200 such as a LAN. Therefore, in addition to line equipment for the PBX constructed for one user, it is required to secure the Internet line 200 such as a LAN taking into account the transmission/reception of the voice information for the-handset.
Further, in the aforementioned Internet telephone system, when a voice connection is made between the PC 7 and the second terminal 92, digital voice information from the PC 7 is converted into an IP packet at an IP converter 61 in the PBX 6, and this packet data is transmitted to the second terminal 92 over the Internet line 200.
In the conventional Internet telephone system described above, if the Internet telephone is one using a PC, there is a problem of lacking in secrecy since speaking contents are output from the speaker of the PC. In order to solve this problem, the technique described in the aforementioned Patent Document 1 improves the secrecy by connecting a handset with a hook switch. However, with the technique of Patent Document 1, the handset is connected with the PC by a wire, so that there is a problem that the movable range of the user using the handset is limited to the length of the cable connecting the handset with the PC.
Even in a case the handset is replaced with the one of a codeless type in order to improve the freedom of the movable range of the user, voice information is transmitted over the Internet line. Therefore, as the number of used IP telephones increases, it is necessary to secure enough bands in the Internet line 200 for coping with the increased number.
Further, in the conventional Internet telephone system, there is a problem that an Internet telephone using the PC cannot be used as a telephone when the power source of the PC is off.
In the technique described in the aforementioned Patent Document 2, although an association between the PC and the terminal is shown, it is so structured that call connection information from the call connection controller is received for a while at an application on the PC, and via a LAN with which the PC is connected, the PC and the existing terminal are associated. Therefore, when a call arrives, the PC and the terminal can be associated. However, if a call is originated from the terminal, origination information is not output from the terminal to the PC. Consequently, the PC and the terminal cannot be associated at the time of origination. This means that in a case of originating from the terminal, the terminal cannot be used as a handset of the PC.
In this case, since the voice information is transmitted/received via the PC and the LAN, if the number of PCs having the Internet telephone function increases, it is necessary to secure the enough bands of the LAN corresponding to the increase. Again, there is a problem that the terminal association at the time of origination cannot be realized if the power source of the PC is off.